June 2015 Elasmobranch of the Month: Smalltooth Sawfish
Species: Smalltooth Sawfish Scientific Name: Pristis pectinata
Key Features: All five shark species in the Family of Pristidae are easily identified by their elongated, blade-like snout, which is stuffed with a number of teeth on either side (the genus name Pristis is derived from the Greek word “pristis,” meaning saw). The smalltooth sawfish, just like it’s name would suggest, has smaller rostral teeth than other members of its family. All sawfish also have flattened, brownish bodies and wing-like pectoral fins. Their mouths are located on the underside of their bodies, called the ventral side, while their eyes are located on the top, or dorsal side. Smalltooth sawfish grow to an average length of 18 feet, while the largest specimen ever caught was 24.7ft in length.
Where it’s found: Smalltooth sawfish are found in the tropical and subtropical Atlantic Ocean, and are usually spotted in coastal habitats like bays, lagoons, and rivers, and favor shallow water over deep. Their geographic range overlaps with the largetooth sawfish (P. perotteti), but there are a few morphological differences between the two, with the smalltooth sawfish having smaller fins and smaller rostral teeth –although the smalltooth sawfish has an average of 12 more pairs of teeth than the largetooth sawfish. Smalltooth sawfish have been reported as being seen all over the world, but scientists believe this is due to misidentification with other species of sawfish.
What it eats: How does the smalltooth sawfish utilize it’s blade-like snout? By swinging it from side to side and impaling fish and other prey on the rostral teeth. The sawfish then scrapes the captured prey off against the bottom substrate and eats it. The saw is also used to help the shark search muddy bottoms for small prey like benthic invertebrates like crabs. Status: IUCN Red List – Critically Endangered, Appendix I of CITES (bans international trade of this species). Sawfish are actually the MOST endangered marine fishes in the world. Threats: The main threats to smalltooth sawfish include being caught as bycatch in various fisheries, especially gill nets, and the loss of habitat favored by juveniles. Their sharp rostrum can easily get caught up in fishing gear, so fishermen used to kill all captured sawfish that they came across while fishing. Juvenile smalltooth sawfish use shallow habitats like mangrove forests and seagrass beds as important nursery areas. Unfortunately, development along coastlines has been responsible for dredging up seagrass areas and removing mangroves, giving the sawfish less and less protected habitat for juveniles. As a result, smalltooth sawfish are now protected under the Endangered Species Act and it is illegal to catch or harm any of these sharks.
If you see a sawfish be a citizen scientist and REPORT IT HERE
Fun Facts: The “teeth” on a sawfish’s snout are not actually true teeth (like the ones found in their mouth), but instead modified scales!
The pups are born with a sheath over the rostrum to protect their mother during live birth.
A recent study has found that females can actually have ‘Virgin Births,” or parthenogenesis. This means she does not have to mate in order to have pups. READ MORE HERE